Editor's note: Blockchain involves many technologies, from the bottom layer of the Internet to the unknown cryptography, but there are often many people who pay attention to currency prices and few people who study technology. During the bull market, everyone will study hard to speculate in coins. During the bear market, there is nothing to do anyway, so I think we can study harder. As a liberal arts student, I certainly have a lot of questions that science students seem to think are idiotic. As a reporter, it is not difficult for me to find people who understand the industry to explain to me in human terms, and they often do not dislike me face to face.
Editor's note: Blockchain involves many technologies, from the bottom layer of the Internet to the unknown cryptography, but there are often many people who pay attention to currency prices and few people who study technology. During the bull market, everyone will study hard to speculate in coins. During the bear market, there is nothing to do anyway, so I think we can study harder. As a liberal arts student, I certainly have a lot of questions that science students seem to think are idiotic. As a reporter, it is not difficult for me to find people who understand the industry to explain to me in human terms, and they often do not dislike me face to face.After that, I want to learn about random algorithms, open source history and culture, etc. If you have other interesting questions, please contribute and ask questions.
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The hottest thing in the currency circle in the past two days is the BCH computing power war. However, in each group, there are still a bunch of people who don't know the truth and pop up such questions during the discussion of the war: "So what are they fighting for?" After popularizing the basic concepts with my friends and various groups, I found that it was not possible. The workload of oral science popularization was too much, so I decided to write an article. This article is based on my interviews and reports on the fork of BTC and BCH, and I asked the interviewee for advice. I am not a technical student. If there are any problems in the text, please correct me.
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What is a fork?
The term fork is mainly applicable to public chain networks such as Ethereum and Bitcoin, and can also be understood as making some modifications based on the original software version. To put it bluntly, you have to download the client software for mining. Bitcoin miners actually use the client to mine. In the way of the Internet, it is a bit like the client is doing "software upgrades".
For example, forking is a bit like after Google created the Android system, allowing developers to make some modifications to the Android system, but not allowing particularly large changes. Compatible, the user can only choose to run one system.
(Don’t ask me why I use Android as an example instead of WeChat, because WeChat is not open source at all, and not everyone can copy its code, which is completely different from Bitcoin. Android is already the open source software I can think of that is used by the most people Yes. Some friends said they couldn’t understand the Android example, so I’ll use the throne example—it’s easier to understand but less accurate.)
Similar forks may occur in the following situations:
1. The version is replaced normally, and the core development team performs software upgrades by themselves (the throne is replaced normally):
Bitcoin, Ethereum, and BCH have all been "officially upgraded" many times. In fact, the previous TheDAO attack on Ethereum ended with a referendum by the whole community, deciding to fork, abandoning the version that was originally hacked, and getting back your own money.
2. Other developers made some changes to the main chain code and released a chain (a new dynasty was born next door):
For example, many early currencies such as Litecoin and Dogecoin copied the Bitcoin code, made some modifications, and issued a chain by themselves. So objectively speaking, these coins are called "fork coins" or "competitive coins", and Bittheists usually call them "cottage coins"-the implication is "cottage" bitcoin coins.
In essence, the birth of BCH also belongs to this kind, but BCH "played relatively big" at the beginning. After all, it was born when everyone was surprised after experiencing the expansion consensus: the Bitcoin ABC team unilaterally forked out Bitcoin Cash, namely BCH , dubbed a "coup d'etat" by the community.
Since Jihan Wu and ViaBTC, a mining pool invested by Bitmain, first announced their support for BCH, some people believed that the birth of BCH was a conspiracy by Jihan Wu. But this statement was denied by BCH and Wu Jihan, and later Bitcoin Jesus also publicly supported BCH, and BCH gradually became the forked currency with the largest market value.3. Other developers in the community are not very happy, so they make a chain by themselves (the drama of seizing the throne):
This is actually the second type. The difference is that there are more dramas of this kind, often involving "fighting for fame" - the crown prince is about to ascend the throne, and the second prince comes out and says that I am the next king - whoever wins depends on who gets the title. The support is much. For example, before the BTC fork, the community originally thought that a computing power vote was about to start.
(In order to avoid ambiguity, I will not explain hard fork and soft fork. The above mentioned belongs to hard fork. Friends who want to know can seeThis article. Let me state that this part is a bit different from what we usually say that there will be forks in mining occasionally. This fork is temporary and will eventually be unified. )
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What's different about this battle of computing power?Which of the above situations is this calculation war? Because the above situations are actually classified according to the identity of the version/software publisher, it is considered the third type. However, CSW's approach is different from that of BCH, which was forked from Bitcoin at that time.
This time, neither party has turned on "replay protection", which means that they are still in the same chain and can only live on one side.
You may be wondering, what is replay protection?
Generally speaking, when the main chain network of the blockchain undergoes a hard fork, the blockchain will permanently diverge and generate two chains that completely correspond to historical transactions, addresses, private keys, and balances. The addresses and private key production algorithms of these two chains are the same, and the transaction format is also exactly the same. In theory, they can be confirmed and identified on both chains, so the transaction you initiate on one of the chains can be sent to the other. Rebroadcasting on the chain may also be confirmed.
For example, after the hard fork of Ethereum from ETC to ETH, hackers continued to charge (ETH) and withdraw (ETH) on the exchange, which caused the exchange to lose a large amount of ETC inexplicably. This is a "replay attack". (In fact, no exchange thought that there were still miners mining on ETC.)
If you add replay protection, you can avoid this situation. The specific way is to change the code, add random numbers, timestamps, or serial numbers, etc., to form isolation between the two chains, so that transactions on one chain Invalidation on the other chain is identified to ensure that the two data sharing chains remain operating independently.Therefore, if both parties do not change the code, there will be no fork, and then the computing power war can only be launched according to the "longest chain principle". The "longest chain principle" is the rule set by Bitcoin, because there are some "temporary forks" in Bitcoin itself, and the nodes should choose which chain to dig down on according to the "longest chain principle"— — This translation is actually a bit problematic,The "longest chain" is precisely "the chain with the largest computing power and high cumulative difficulty".
Jiang Zhuoer wrote in his article that, for example, nodes will accept 2 blocks with a difficulty of 10 and discard 3 blocks with a difficulty of 5, because 10+10=20>15=5+5+5. However, in general, the greater the computing power, the faster the block will be produced, because it takes a certain amount of time to adjust the difficulty.
This is the way of the current computing power war: ABC and BSV use the existing computing power to choose different clients for mining and mine a longer chain.
In theory, neutral/rational nodes will accept a longer chain according to the rules, because this chain will survive according to the rules-the problem is that these two sides are not playing according to the rules or rationally.At present, even if the computing power of BSV is temporarily behind, as long as there is computing power to keep digging on a certain chain, this chain will always exist.
Until any party gives up and no longer invests in any computing power, this chain will not exist, and the coins he originally dug up will be equivalent to returning to zero—this is called surrender. Of course, he also has another option, which is to turn on replay protection or modify the algorithm - which is equivalent to declaring independence and finally splitting into two coins.
The war started when ABC released the hard fork plan in November, and CSW said in August that a new version would be released, and what he meant was "I don't want the original version, but I also split and don't want to be independent, that is I want to take ABC and replace it." Whether there will be two kinds of coins in the final result depends on what both parties think.
Of course, in fact, there is a more "rude" way to fight the computing power, which is to use one's own computing power advantage to directly block the opponent's chain with computing power, making it impossible to trade. In fact, it is a 51% computing power attack, and the specific effect that can be achieved Jiang Zhuoer also said:
Through 51% attacks, various purposes can be achieved, such as:
1. After Tx1 (transaction 1) is confirmed, cancel Tx1 and let another conflicting Tx2 (transaction 2) take effect.2. Use the blocks dug by yourself (red blocks) to isolate the blocks dug by other miners (blue blocks), so that other miners will lose mining output.
However, both parties did not use this method, perhaps because of economic reasons or because they felt that this matter was "unjust", but the real reason is only known to both parties.
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What does the exchange do?
If no one surrenders or unilaterally becomes independent, theoretically the exchange will stop withdrawing or recharging. Now it is an intermediate state, it is not known which chain will win, and no new coins have been generated yet. Exchanges cannot list spot trading pairs, but at most they can list futures.
However, once it is really split into two coins, the choice of the exchange is very important what is the fate of the split coin. Assuming that the BSV currency was born as a currency, but there is no such currency on the exchange, it cannot be traded and there is no market price, no one will be willing to mine this currency, because mining is meaningless. To put it bluntly, miners are willing to mine BCH essentially to make money, so the price is often proportional to the computing power.
This is why Wu Gang, an old man in the currency circle, said that computing power is only part of the consensus, not all.
However, exchanges that only support one side may be rare. For the benefit of users, there is a high probability that exchanges are neutral. If there are two coins, I will support them and issue them to users at the same time, and then slowly list the trading pairs. For example, Binance’s announcement is a typical neutral:
To support the BCH hard fork, Binance will take a snapshot at 0:40 on November 16, and suspend BCH deposits and withdrawals at 23:00 on November 15. Due to the possibility of Bitcoin Cash ABC (BCHABC) and Bitcoin Cash SV (BCHSV) appearing in the BCH hard fork, Binance will suspend BCH/BNB, BCH/BTC, BCH/ETH, and BCH/USDT at 0:40 on November 16 For transaction pairs, the follow-up processing plan is as follows:
Xiao Ming's study notes | One article to understand the verifiable random function VRF
I am Lu Xiaoming, editor of Odaily. I am exploring the real blockchain. Please add lohiuming for breaking news and communication. Please note your name, unit, position and reason.
The first period of learning before is the virtual machine ("Xiao Ming's Study Notes | Understand the Blockchain Cross-Chain Mechanism in One Article"), the second phase is cross-chain ("Xiao Ming's Study Notes | Understand the Blockchain Virtual Machine in One Article"), Issue III"Xiao Ming's Study Notes | Understand the Internet TCP/IP Protocol in One Article", the fourth issue is "Xiao Ming's study notes | One article to understand the verifiable random function VRF》
Related Reading:
The battle for Bitcoin expansion, will the revolution go to the future, or will it split?
What is a hard fork, what is a soft fork, and what is consensus?
In-depth Bitcoin Principles (13) - Hard Fork and Soft Fork
BCH fork has no replay protection, what does it mean?
